JavaSE-Stream流的中间方法

目录

Stream流的中间方法

filter

limit

skip

distinct

concat

map

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Stream流的中间方法

filter

案例：过滤出以张开头的元素

public class StreamDemo6 {
    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<>();
        Collections.addAll(list,"张无忌","周芷若","赵敏","张强","张三丰","张翠山","王二狗","谢广坤");
        list.stream().filter(s->s.startsWith("张")).forEach(s-> System.out.println(s));
    }
}

打印结果：

limit

案例：获取前三个元素

public class StreamDemo7 {
    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<>();
        Collections.addAll(list,"张无忌","周芷若","赵敏","张强","张三丰","张翠山","王二狗","谢广坤");
        list.stream().limit(3).forEach(s-> System.out.println(s));
    }
}

打印结果：

skip

案例：跳过前三个元素

public class StreamDemo8 {
    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<>();
        Collections.addAll(list,"张无忌","周芷若","赵敏","张强","张三丰","张翠山","王二狗","谢广坤");
        list.stream().skip(3).forEach(s-> System.out.println(s));
    }
}

打印结果：

distinct

案例：去除重复的元素

public class StreamDemo9 {
    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<>();
        Collections.addAll(list,"张无忌","张无忌","张无忌","周芷若","赵敏","张强","张三丰","张翠山","王二狗","谢广坤");
        list.stream().distinct().forEach(s-> System.out.println(s));
    }
}

打印结果：

concat

案例：合并list1和list2的流

public class StreamDemo10 {
    public static void main(String[] args) {
        ArrayList<String> list1 = new ArrayList<>();
        ArrayList<String> list2 = new ArrayList<>();
        Collections.addAll(list1,"张无忌","周芷若","赵敏","张强");
        Collections.addAll(list2,"张三丰","张翠山","王二狗","谢广坤");

        Stream.concat(list1.stream(),list2.stream()).forEach(s-> System.out.println(s));
    }
}

打印结果：

map

案例：获取每个元素的年龄

public class StreamDemo11 {
    public static void main(String[] args) {
        ArrayList<String> list1 = new ArrayList<>();
        Collections.addAll(list1,"张无忌-19","周芷若-20","赵敏-30","张强-40");
        list1.stream()
                .map(s->Integer.parseInt(s.split("-")[1]))
                .forEach(s-> System.out.println(s));
    }
}

打印结果：